I have been wondering if I should buy a case for my iPhone 4 but decided that I wanted to have it as "nude" as possible. My plan is to have a protective film on the front and back and use Apple's bumper case. After some research, I discovered that SGP made some decent screen protectors and went with the SGP Steinheil EX Ultra Crystal.
The whole package was $22 and comes packed with everything you need to get the perfect application. I purchased it off of this seller on ebay by the way.
Here is the meat of the package. It comes with 2 sets of front and back protection. Yes, 2 sets. Considering that these are pretty decent screen protectors, this product is a rather good deal.
Here is the result. The film is made of aluminosilicate glass and has a silicone adhesive. Although they call it "glass" - it'll still feels and scratches like plastic. Neverthless, the result is pretty good.
The film is definitely "ultra crystal" as SGP's marketing calls it. No rainbowing, no distortion, just pure retina display.
The SGP is significantly thicker than most of the screen protectors. With the flash on, you can easily see the film's thickness. The yellow is from the flash so don't worry about the film having a tint.
Now here are its issues. Due to the thickness of the film, there is a bit of lifting on the edges of the film. I found that it's possible to remove them by constantly pushing down with your fingernails. It's a non-problem once you get rid of them but is still irritating. As you can see, I still have an area around the camera that needs some work.
The film is also a fingerprint magnet. Once you put the film on, you immediately realize the effectiveness of an oleophobic coating. SGP does sell a version with an oleophobic coating but does not include protection for the back. I've also heard that Power Support makes good screen protectors.
Despite its the downfalls, I'm happy with the results.